Litjens PEMH, Van Willigen G, Weeterings C, Ijsseldijk MJW, Van Lier M, Koivunen E, Gahmberg CG, Akkerman JWN. A tripeptide mimetic of von Willebrand factor residues 981-983 enhances platelet adhesion to fibrinogen by signaling through integrin alpha(IIb)beta3.
J Thromb Haemost 2005;
3:1274-83. [PMID:
15946218 DOI:
10.1111/j.1538-7836.2005.01408.x]
[Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022]
Abstract
BACKGROUND
RGD is a major recognition sequence for ligands of platelet alpha(IIb)beta3.
OBJECTIVE AND METHODS
To identify potential binding sites for alpha(IIb)beta3 apart from RGD, we screened phage display libraries by blocking the enrichment of RGD-containing phages with a GRGDS peptide and identified a novel integrin recognition tripeptide sequence, VPW.
RESULTS
Platelets adhered to an immobilized cyclic VPW containing peptide in a alpha(IIb)beta3-dependent manner; platelets and alpha(IIb)beta3-expressing CHO cells adhered faster to immobilized alpha(IIb)beta3-ligands in the presence of soluble VPW. In platelets adhering to fibrinogen, VPW accelerated the activation of the tyrosine kinase Syk which controls cytoskeletal rearrangements. In alpha(IIb)beta3-expressing CHO cells, VPW induced a faster formation of stress fibers. Sequence alignment positioned VPW to V980-P981-W982 in the von Willebrand factor (vWf) A-3 domain. In blood from a vWf-deficient individual, VPW increased platelet adhesion to fibrinogen but not to collagen under flow and rescued the impaired adhesion to vWf deficient in A-3.
CONCLUSION
These data reveal a VPW sequence that contributes to alpha(IIb)beta3 activation in in vitro experiments. Whether the V980-P981-W982 sequence in vWf shows similar properties under in vivo conditions remains to be established.
Collapse